Automated Bridge Scour Inspection

nutmegactSoftware and s/w Development

Nov 10, 2012 (4 years and 5 months ago)

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Automated Bridge Scour

Inspection

FSU/FAMU College of Engineering

Team 7



Concept Design Review

12/1/2010

Revised System

Vertical Motion

Design Updates / Improvements

-

Concepts considered

-

Selection criteria

-

Risks associated with selection


Schedule / Budget Updates

-

Analysis time exceeded

-

Fabrication time overestimated

-

Proposed equipment within budgeted amount






Vertical Motion


Analysis Method / Assumptions

-

Operating parameters for DC Motor

-
Critical Operation Point

-

Gearing for adequate ascent/descent speed


Analysis Results

-

Minimum load torque: 6.5 N*m

-

5:1 gear reduction ratio

-
Adequate speed: 20 cm/sec

-
Sufficient output torque: 32 N*m





Vertical Motion

Revised Specification

-

System weight inflated 10%: 44 lbs.

-

Motor load under 80%


Proposed Equipment

-

Maxon Motors RE 35 Brushed DC Motor


-
24V Operation

-

Maxon Motors 32 HP Planetary Gearhead

-
28:1 Reduction ratio

-

Combined Cost: $ 468.00




Vertical Motor Performance

Circumferential Motion

Design Updates / Improvements

-

Concepts considered

-

Selection criteria

-

Risks associated with selection


Schedule / Budget Updates

-

Analysis time overestimated

-

Fabrication time overestimated

-

Proposed motor within budget amount

-

Guiderail cost pending






Circumferential Motion


Analysis Method / Assumptions

-

Operation at low speed, low displacement

-
Low drag

-

Focus on precision positioning


Analysis Results

-

12 V DC Motor

-

Minimum 200 oz
-
in stall torque






Circumferential Motion

Proposed Equipment

-

Pololu 12V 131:1 DC Gearmotor

-

Combined 64 CPR Encoder

-

Cost: $ 40.00




SONAR Tilt

Design Updates

-

Maintain previous design

-

Lower priority

-

Low risk


Schedule / Budget Updates

-

Analysis and specification pending

-

Budget on par





Design Structure


Design Updates and Improvements


Circular Guide Rail


Component Housing


Localization


Risks


Design Updates

and
Improvements


Circular Guide Rail


Bishop
-
Wisecarver


Single Edged PRT


24” Diameter


11.5 lbs


Custom Hinge




Component Housings


Locker 2 by Witz


Size


Pressure



Localization


Motor + Encoder


Accuracy




Risks


Ring Design


Custom



Waterproof


Exit Holes



Encoder Accuracy


Power

Old Design


Use 2 separate battery sources


-

DC Motors, Motor Controller
-

AGM battery


-

Microcontroller, Sensors
-

NiMH


Better efficiency, less power loss


The New Design


-

Motor Driver outputs 5V for













Microcontroller,Sonar,servo. Eliminates 2
nd

battery


-

Use 1 LiFePO4 or SLA Battery to power







everything



Block Design for Powering
Components






-

Motor Driver has a feature that can power the
DC motors and also some low power
components.

Sabertooth dual 25A motor driver

Controls

2

Brushed

DC

Motors

independently

5
V

Output

Terminal

for

Microcontroller

Power


Lithium

protection

mode

Built
-
in

Overcurrent

&

Thermal

Protection

Screw
-
in

Terminals

for

Easy,Secure

Connections

Continuous

Output

per

channel

25

Amps

Peak

Output

per

channel

50

Amps

Nominal

input

Voltage

6
-
24

Volts

Max

Voltage


30

Volts

Size


2
.
6
''x
3
.
2
''x
0
.
8
''

DC motors

Vertical motion motor

-

Nominal Voltage 24V

-

Starting Current 41A

-

Cont. Current 3.36A



Circumferential motion
motor

-

12V ~300mA

Battery

-

Weight and Cost are issues


-

Lead Acid vs Lithium Polymer


1. Sealed Lead Acid Battery




-

Cheaper, but heavier



2. Polymer LiFePo4 Battery


-

More expensive, but lighter



Technical Risks


-

hook up battery to motor driver reverse polarity.


This will damage and void the driver!! Add a diode to
prevent this. Product is expensive ~$125


-

Motor overheating,


The motor driver peaks at 50Amps and has over
-
current protection built
-
in. DC motors are within the
motor driver's capabilities...6V
-
24V


continuous run < 25Amps. Starting run < 50Amps





The Next Step..


-

Choose battery type and capacity Ah


-

Choose/Purchase DC Motors and Motor




Controller


-

Purchase a Battery for testing purposes


-

More detailed design to integrate into system


(wiring, positioning electronics in casing,


protection, i.e.)

Microcontroller

Beagle Board



$149




ARM
®

Cortex
TM

A8 MHz @
1 GHz




LPDDR RAM
512MB




SD Card Expansion




3D graphics accelerator




5 Volts




16 I/O IC2 ports




RS
-
232 Port




Large active community


Autonomous Programming



Language
-

C++




Computer Environments


-

Eclipse


-

Netbeans




Beagle Board Packages


-

Bash task


-

Nativ
-
sdk


-

gdb


-

samba





Autonomous Programming



3 Modules


-

Vertical Movement


-

Circumference Movement


-

Sonar Servo Movement




Outputs


-

Motor Controller


-

Servo




Inputs


-

Encoders


-

Sonar

Current Progress

-

Preliminary pseudo code finished


-

Detailed information on I/0
Communication


-

Write Detailed pseudo code


-

Begin programming using Eclipse
and/or Netbeans




Technical Risk



Inefficient amount of I/O pins




IC2 1.8V Tolerance




Microcontroller shortage





SONAR


Old Design:


Test multiple sensors


Use Fish Finder transducers


Lower costs


Compatibility issues w/ microcontroller


Time Constraints



New Plan:


Only test 1 or 2 sensors


SONAR altimeters


Higher costs


Connect directly to microcontroller via RS
-
232


Benthos PSA
-
916

Frequency: 200 kHz

Beam Width: 14 degrees conical

Range: 0.8 m


100 m

Output: RS
-
232 (digital)


0


5 VDC (analog)

Resolution: RS
-
232: 1 cm


Analog: 2.5 cm

Power: 6


24 VDC; 100mA @ 6V

Dimensions: 2.25” Diameter X 9.38”
Long

Weight: 1.4 lb (air); 0.8 lb (water)


Kongsberg 1007 Series

Frequency: 675 kHz

Beam Width: 2.5 degrees
nominal

Range: 0.61 m


30.48 m

Output: RS
-
232; 9600 baud rate

Resolution: 2.4 mm

Power: 22


26 VDC; 250mA

Dimensions: 3.49” Diameter X
7.75” Long

Weight: 5.2 lb (air); 2.4 lb (water)


Tritech PA500

Frequency: 500 kHz

Beam Width: 6 degrees conical

Range: 0.3 m


50 m

Output: RS
-
232; 9600 baud rate

Resolution: RS
-
232: 1 mm


Analog: 0.025%

Power: 24 VDC @ 80 mA; 12
VDC @ 160 mA

Dimensions: 1.85” Diameter X
6.30” Long

Weight: 2.43 lb (air); 1.76 lb
(water)


Risks


Physical Damage to sensor


O
-
ring


Abrasion from sediment


Operation Angle


Weak Signal Received


Obstacles


Budget

Schedule